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4．简单的例子

     以上流程中使用到的Java源代码和配置文件如下：

// MyPrincipal.java package com.jungleford.auth; import java.security.Principal; public class MyPrincipal implements Principal { // 一个Principal的例子 private String name; // Principal的名字 public MyPrincipal(String name) { this.name = name; } public String getName() { //取得Principal的名字 return this.name; } public boolean equals(Object principal) { // 判断两个Pincipal相同的依据 if (principal instanceof MyPrincipal) return this.name.equals(((MyPrincipal)principal).getName()); else return false; } public String toString() { // Principal的表示 return "MyPrincipal: " + this.name; } public int hashCode() { // 确定本对象的散列值 // 用于有基于散列容器的场合，判断在散列容器中是否是同一个对象。 // 如果对hashCode感兴趣，请参见： // http://www-900.ibm.com/developerWorks/cn/java/j-jtp05273/ return this.name.hashCode(); } }

// MyLoginModule.java package com.jungleford.auth; import java.util.*; import java.io.IOException; import java.security.Principal; import javax.security.auth.*; import javax.security.auth.callback.*; import javax.security.auth.login.*; import javax.security.auth.spi.*; public class MyLoginModule implements LoginModule { // 一个登录模块的例子 private Subject subject; // 登录主体的表征 private CallbackHandler cbHandler; // 回调对象，提供终端下获取用户名、口令的界面 private Map sharedState; // 用于缓存中间结果的共享区 private Map options; // 用于保存某些登录模块所需要用到的一些配置选项 private boolean succeeded = false; // 一次login成功的标志 private boolean cmtSucceeded = false; // 整体登录成功的提交标志 private String username; // 取得用户名 private char[] password; // 取得口令 private Principal principal; // 取得登录后的身份标志 public void initialize(Subject subject, CallbackHandler cbHandler, Map sharedState, Map options) { // 初始化过程 System.out.println("Login module initializing ..."); System.out.println(); this.subject = subject; this.cbHandler = cbHandler; this.sharedState = sharedState; this.options = options; } public boolean login() throws LoginException { // 一次登录过程 if (cbHandler == null) // 尚未配置回调对象 throw new LoginException("Error: No CallbackHandler available " + "to garner authentication information from the user"); Callback[] cbs = new Callback[2]; // 仅使用用户名回调和口令回调 cbs[0] = new NameCallback("Login: "); cbs[1] = new PasswordCallback("Password: ", false); try { cbHandler.handle(cbs); username = ((NameCallback)cbs[0]).getName(); char[] temp = ((PasswordCallback)cbs[1]).getPassword(); if (temp == null) { // 口令为空 temp = new char[0]; } password = new char[temp.length]; System.arraycopy(temp, 0, password, 0, temp.length); ((PasswordCallback)cbs[1]).clearPassword(); // 清除内存中的口令痕迹 } catch (IOException ioe) { throw new LoginException(ioe.toString()); } catch (UnsupportedCallbackException uce) { throw new LoginException("Error: " + uce.getCallback().toString() + " not available to garner authentication information " + "from the user"); } boolean usrCorrect = false; // 用户名正确否？ boolean pwdCorrect = false; // 口令正确否？ if (username.equals("user")) // 目前仅允许用户名为user的登录 usrCorrect = true; if (usrCorrect && password.length == 9 && password[0] == 'l' && password[1] == 'e' && password[2] == 't' && password[3] == 'm' && password[4] == 'e' && password[5] == 'p' && password[6] == 'a' && password[7] == 's' && password[8] == 's') // user的口令指定为letmepass { System.out.println("MyLoginModule: Authentication pass!"); System.out.println(); pwdCorrect = true; succeeded = true; return true; // 一次登录成功 } else { System.out.println("MyLoginModule: Authentication failed!"); System.out.println(); succeeded = false; username = null; for (int i = 0; i < password.length; i++) // 清除内存中的口令痕迹 password[i] = ' '; password = null; if (!usrCorrect) { throw new FailedLoginException("Username incorrect!"); } else { throw new FailedLoginException("Password incorrect!"); } } } public boolean commit() throws LoginException { // 根据登录配置策略判断是否整体登录成功 if (succeeded == false) { return false; } else { principal = new MyPrincipal(username); if (!subject.getPrincipals().contains(principal)) subject.getPrincipals().add(principal); // 把新的身份添加到subject中 System.out.println("MyLoginModule: Add a new principal to current subject."); System.out.println(); username = null; for (int i = 0; i < password.length; i++) // 清除内存中的口令痕迹 password[i] = ' '; password = null; cmtSucceeded = true; return true; } } public boolean abort() throws LoginException { // 放弃登录，将状态复位至登录前 if (succeeded == false) { return false; } else if (succeeded == true && cmtSucceeded == false) { succeeded = false; username = null; if (password != null) { for (int i = 0; i < password.length; i++) // 清除内存中的口令痕迹 password[i] = ' '; password = null; } principal = null; } else { logout(); } return true; } public boolean logout() throws LoginException { // 注销，并将状态复位至登录前 subject.getPrincipals().remove(principal); succeeded = false; succeeded = cmtSucceeded; username = null; if (password != null) { for (int i = 0; i < password.length; i++) // 清除内存中的口令痕迹 password[i] = ' '; password = null; } principal = null; return true; } }